There is a great need in agricultural and gardenproduce growing industries for to grading different products according to their size, in a smooth and trouble-free fashion. Mechanical and electronic grading systems are known in the art. The mechanical systems cause damage to the products and do not result in uniform grading. The electronic systems sort the products singly in a channel or like conveyer, see for example, GB-A-1 571 889, U.S. Pat. No. 4,558,786, U.S. Pat. No. 1,722,751, U.S. Pat. No. 3,708,065, SU-749 456, SU-1 187 740, SU-749 456. Most of these systems are highly expensive in operation at normal capacity requirements.